A91/100
CONTRA COSTA WATER DISTRICT — Water Quality Report 2026
Serving 198,000 people · California
Water Source
Surface Water
County
—
System ID
CA0710003
Violations
2
Contaminant Test Results
1 contaminant above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
Lead (90th percentile) | 0.003 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
No violations in the past 5 years
Full EPA compliance since 1999.
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Frequently Asked Questions About CONTRA COSTA WATER DISTRICT
Is CONTRA COSTA WATER DISTRICT water safe to drink?
CONTRA COSTA WATER DISTRICT water receives a grade of A (91/100), which is considered excellent. Out of 76 contaminants tested, none exceed EPA legal limits. 1 contaminant(s) exceed non-enforceable health goals. The water meets federal safety standards.
What contaminants has CONTRA COSTA WATER DISTRICT detected?
76 contaminants were tested in CONTRA COSTA WATER DISTRICT's water. Notable contaminants include Lead (90th percentile). No contaminants exceed EPA legal limits. 1 exceed EPA health goals (MCLGs).
Does CONTRA COSTA WATER DISTRICT have any EPA violations?
Yes, CONTRA COSTA WATER DISTRICT has 2 EPA violation(s) on record, with the most recent in 1999. Violation types include TT, Other. 1 are health-based violations.
How many people does CONTRA COSTA WATER DISTRICT serve?
CONTRA COSTA WATER DISTRICT serves approximately 198,000 people, California.
What type of water does CONTRA COSTA WATER DISTRICT provide?
CONTRA COSTA WATER DISTRICT sources its water from surface water. Surface water comes from rivers, lakes, or reservoirs and typically requires more extensive treatment. The utility's system ID is CA0710003.
How does CONTRA COSTA WATER DISTRICT compare to other utilities in California?
CONTRA COSTA WATER DISTRICT scores 91/100 with a grade of A (excellent). This places it among the higher-performing utilities in the state. Visit our California state page for a full comparison of water systems.